The cell is outlined in purple by structures called actin stress fibers, which essentially form a tiny skeleton made of protein that helps give the cell its shape. The yellow spaghetti-like structures are groups of mitochondria, a small structure within the cell that helps convert sugars and other energy sources into the ATP that powers most proteins. Finally, the nucleus glows blue thanks to a dye called DAPI that sticks to DNA. In this case, the image is magnified at 63x, and is the merger of three separate images, one for each color.